There may be dozens or even hundreds of Virtual Machines (VMs) that are hosted on an individual physical server by employing the server virtualization technology, so that the utilization of the server is improved. In order to enhance the high availability of the server, VMs may be migrated between different ports of an access layer device or migrated between different access layer devices. Different standards organizations have developed different standardized protocols, such as the Transparent Interconnection of Lots of Links (Trill) protocol, the Shortest Path Bridging (SPB) protocol, etc., which can be used to build a Very Large Layer 2 (VLL2) network to achieve the migration of VMs.
Taking a VLL2 network including a plurality of Data Centers (DCs) as an example, the VLL2 networking technologies include VLL2 network technologies within a DC and VLL2 network technologies interconnecting DCs. The former can achieve the VM migration between different ports of an individual access layer device and the VM migration between different access layer devices within an individual DC. The later can achieve the VM migration between access layer devices belonging to different DCs.